Impact tool tester



Sept. 6, 1966 E. SUSSMAN IMPACT TOOL TESTER Filed May 13, 1 963 INVENTOR ATTORNEYS United States Patent 3,270,550 IMPACT TOOL TESTER Ernst Sussman, Bierys Bridge Road, Bethlehem, Pa. Filed May 13, 1963, Ser. No. 279,982

r Claims. (Cl. 73-11) This invention relates to testing devices for measuring impact and more particularly to such devices as are appropriate to the testing of the force of the blow delivered by an impact tool.

The general object of the invention is to provide a novel and improved testing means of this type which is of simple and relatively inexpensive construction and which will yield a measure of the impact delivered by the projecting spring employed in a manually operated impact tool, Whether a punch, and insertion tool as for attaching electric conduits, or projectable tools for a wide variety of other purposes.

In its preferred embodiments, the invention contemplates the provision of a solid base structure upon which is disposed a pad or pack of superposed sheets of paper or other transfer material, whereby a blow delivered at a relatively concentrated point upon the top sheet of the pad will cause the underlying sheets to transfer a visible impression of the point of the tool or instrument through such number of sheets as corresponds to the intensity of the impact.

The device is well adapted to test and calibrate impact tools of the class described in my co-pending application Serial No. 151,970, filed November 13, 1961. Such tools are adapted to be pressed against the work and pressure applied to the shanks or handles thereof until the projecting or propelling spring within the tool is triggered or tripped to drive a hammer against an anvil carried by the projecting tool head. In this way a blow or impact of measured predetermined force may be applied to the work.

In order to calibrate such a tool and accurately predetermine the delivered impact force, the operative tool head may be replaced by a dummy head or special nose piece terminating in a hardened small steel ball, and this ball is brought into contact with the top sheet of the novel testing device, pressure applied in the usual way and the blow delivered by the tripping of the projecting spring within the tool.

Preferably, the sheets of pressure-sensitive paper comprising the pack or pad are marked off into identical areas whereby the assembly may be used a number of times; and tabs may be applied to the successive sheets which are numbered so as to more quickly determine the number of sheets through which the visible impression persists and thus yield a record of the force of the impact.

Other objects and features of novelty will be apparent from the following specification when read in connection with the accompanying drawings in which one embodiment of the invention is illustrated by way of example.

In the drawings:

FIGURE 1 is a side view with a portion of the tool shank broken away, disclosing one form of tool which can be tested or calibrated by the device according to the present invention;

FIGURE 2 is a view in perspective of the device which is the subject of the invention; and

FIGURE 3 is a similar view showing a number of the sheets of the test pad turned back to ascertain the furthest point of penetration of the test impression.

In the drawings, the numeral designates generally a tool represented, for example, by the one described in my aforesaid pending application. The body portion 11 of the tool receives a projectable tool shank 12 which is providedwith a threaded socket 13 into which any type of replaceable impact tool head may be inserted. The tubular handle portion 15 of the tool is adapted to be pressed forwardly after the head of the tool has been applied to the work and at a certain point in its forward movement the handle triggers a projecting spring which causes a hammer to impinge forcefully upon an anvil which is fixed with relation to the tool stem 12, all whereby an impact of predetermined force is applied to the tool.

In testing a tool of this nature, it is preferred that a special nose piece indicated at 20 in FIGURE 1 be inserted in the socket 13 in lieu of whatever working tool might be regularly employed. The nose 20 has a threaded shank 21 adapted to be screwed into the socket 13 and a tapering forward end 22 terminating in a small hardened steel ball 25. For the better application of a tool for applying and removing the nose 20, opposite faces thereof may be flattened as suggested at 26.

The testing device shown in FIGURES 2 and 3 of the drawings comprises a preferably solid rather heavy metal base block 30 of any suitable configuration such as provided by the bevelled edges 31. Such a heavy metal base provides a kind of anvil, which has no such resiliency as might give rise to inaccurate readings through the relatively soft pad. A hook-like metallic gripping or clamping member is fixedly secured to one edge of the base 30. This device in the preferred embodiment is shown at 35 as a resilient metal spring plate having a returnbent portion 36 terminating forwardly in a rolled or curled edge 37.

A pad of pressure sensitive sheets of paper or other material, indicated at 40, is disposed upon the top of the base 30 and one edge securely clamped beneath the edge 37 of the clamping device 35.

In the illustrated example, twelve sheets are provided, but this number may be varied to take care of various ranges of impacts afforded by the tools to be tested. For convenience, the sheets are cut away to provide an echelon arrangement of projecting tabs as at 42, the tabs being numbered in accordance with the sheets in descending order.

The individual sheets 45 comprising the stack 40-or at least all of the underlying sheets except the top one may be made of transfer paper and preferably of the kind designated NCR (No Carbon Required) put out by National Cash Register Company. As is well known, pressure at a point on an overlying sheet will cause an impression of that point to visibly appear on the underlying sheet, whether the impression is delivered by a pen, a pencil, the key of a writing machine, or by any other localized instrumentality. Thus, in most cases, it is not of too great importance that sheet #1 designated 45a be of this same variety just so the subsequent sheets will be marked by the impression passing through the upper sheets. However, for true calibration of the device the top sheets should be of uniform gauge and quality.

On the other hand, it is desirable that the impression on the first sheets be permanently perceptible and that a second impression could not be made without detection. Therefore, in one preferred embodiment of the invention, the top sheet 45a comprises a sheet of metallic foil superimposed on the NCR paper, and desirably the foil sheet should be covered with a very fine matte to protect it from scratches and soiling.

The stronger and more localized the point of impression is the more copies of the impression can be made. Thus, the use of such paper in a pack or pad as in the present case will give an accurate determination of the intensity of the impact delivered by a tool, in accordance with the number of sheets on which the impression of the Patented Sept. 6, 1966- impact occurs in a direction downwardly through the pile.

Thus, the tool 10 may be applied to one of the numbered squares on the top sheet, for example, as at 50 (the underlying sheets also preferably being marked into similarly numbered squares) and the device triggered to deliver a blow.

Then the sheets are successively raised as suggested in FIGURE 3 until the impression of the impact disappears. As could be the case in FIGURE 3, sheet #5 would bear the last marking of the impression of the impact as at 51 and an inspection of sheet #6 would reveal no impression in this square. Therefore, the calibration of the intensity of the impact will be rated at 5, and very obviously the significance of this numerical designation can be translated into terms of force by a pre-calibration of the sheets.

It is understood that various changes and modifications may be made in the embodiment of the invention i1- lustrated and described herein without departing from the scope of the invention as determined by the following claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A testing device for measuring and calibrating the intensity of a blow delivered by an impact tool, said device comprising, in combination, a heavy rigid anvil-like metal base, a pad of pressure-sensitive impression-transferring sheets disposed upon said base, clamping means for detachably securing said pad to said base, a multiplicity of similar areas on each of said sheets upon which the impact delivering head of said tool may be applied and the tool actuated to deliver the blow, indicia correspondingly designating the said areas on all of said sheets, markings thus being impressed upon the surfaces of said sheets in downward succession through the pad through such number of sheets as determined by the force of the blow, each of said sheets provided with a protruding tab, the tabs being numbered successively from top to bottom of the pad, all whereby the number of the last sheet showing an impression yields a measure of the effective impact of the tool.

2. A testing device for measuring and calibrating the intensity of a blow delivered by an impact tool, said device comprising, in combination, a base, a pad of pressuresensitive impression-transferring sheets disposed upon said base, areas on said sheets upon which the impact delivering head of said tool may be applied and the tool actuated to deliver the blow, markings thus being impressed upon the surfaces of said sheets in downward succession through the pad through such number of sheets as determined by the force of the blow, whereby a count of the sheets thus impressed yields a measure of the effective impact of the tool the top sheet comprising a sheet of metallic foil.

3. The testing device as set forth in claim 2 in which the top sheet comprising the sheet of metallic foil is covered with a fine protective matte, to protect said foil from scratching or soiling but not presenting any percepti ble interference to the force of the test blow passing therethrough.

4. The method of testing an impact tool which comprises providing a pad of pressure-sensitive transfer sheets, applying the operating end of said tool to the top sheet of said pad, triggering said tool to deliver a blow downwardly upon the pad, and recording the number of sheets through which the impression persists.

5. The method of testing and calibrating an impact tool which comprises providing a pad of pressure-sensitive transfer sheets, delivering a blow downwardly on such pad by means of a similarly configured instrumentality of known standard impact force thus determining the number of sheets through which standard penetration of impression persists, applying the operating end of the tool to be tested to the top sheet of said pad, triggering said tool to deliver a blow downwardly upon the pad, and recording the number of sheets through which the impression persists, thus giving a comparison of the effectiveness of the test tool with that of the standard tool.

References Cited by the Examiner UNITED STATES PATENTS 2,273,005 2/ 1942 Beach 28211 2,301,005 11/-1942 Bailey 282--22 2,724,601 7/1951 Fuerst et al. 282-28 3,164,237 1/1965 Cappotto 19717 RICHARD C. QUEISSER, Primary Examiner.

r G. M. GRON, Assistant Examiner. 

1. A TESTING DEVICE FOR MEASURING AND CALIBRATING THE INTENSITY OF A BLOW DELIVERED BY AN IMPACT TOOL, SAID DEVICE COMPRISING, IN COMBINATION, A HEAVY RIGID ANVIL-LIKE METAL BASE, A PAD OF PRESSURE-SENSITIVE IMPRESION-TRANSFERRING SHEETS DISPOSED UPON SAID BASE, CLAMPING MEANS FOR DETACHABLY SECURING SAID PAD TO SAID BASE, A MULTIPLICITY OF SIMILAR AREAS ON EACH OF SAID SHEETS UPON WHICH THE IMPACT DELIVERING HEAD OF SAID TOOL MAY BE APPLIED AND THE TOOL ACTUATED TO DELIVER THE BLOW, INDICIA CORRESPONDINGLY DESIGNATING THE SAID AREAS ON ALL OF SAID SHEETS, MARKINGS THUS BEING IMPRESSED UPON THE SURFACES 